Patent GB-1204002-A (GB)
Title: Process for the continuous production of tubular articles made of textile material in particular for use in lead-acid storage batteries
Inventor: EIGENMANN LUDWIG
IPC: H01M4/76
Filed: 1967-11-02
Abstract: 1,204,002. Making tubular elements; laminates. L. EIGENMANN. 2 Nov., 1967, No. 49953/67. Headings B5A and B5N. [Also in Divisions D1, F2 and H1] Tubular elements suitable for use in lead-acid storage batteries, are made by expanding a composite fabric, such as that shown in Fig. 3, by a series of expansible cores. Prior to, or during, the expansion, the fabric is superficially or completely impregnated with a hardenable polymeric material and, during the expansion, this material is hardened to retain the fabric in its expanded shape. Finally the cores are contracted, the shaped fabric removed and the parallel tubes thus formed separated and subdivided into the requiste lengths. The core may comprise tubular rubber elements expanded by internal pressure, the pressure being provided by an internal piston, by compressing one end of the element or by evaporating a liquid contained either within the core itself or within a bulb connected to the core. Alternatively the core may be a helically wound metal strip contractible by pulling its ends in opposite directions or a sheet of metal bent into an overlapping tube. In the examples illustrated in Figs. 9-11 (not shown) the fabric is intermittently drawn over the cores, the cores being expanded during the stationary periods of the fabric and being retained in a fixed position by means such as rollers or electromagnets which co-operate with suitably-shaped ends of the cores. In an alternative variant, the core may be initially moved with the fabric retained stationary during the impregnation and hardening, and subsequently drawn back to its original position by the electromagnet. In Figs. 12-13 (not shown) in which the cores remain stationary, a device is provided to form a concertinaed store of fabric in advance of the core. In the embodiment shown in Fig. 14, unexpanded fabric is intermittently drawn by rolls (131 and 13, see Fig. 15, not shown) through a coating and hardening station 31<SP>1</SP>, the fabric being fed to the chamber by continuously rotating rolls 35 so as to build up a store 36. The fabric and cores are supported within the coating station by freely rotatable rollers 38 carried by chain 39, and during the stationary periods, the fabric is sprayed at a small angle to its surface by sprays 40, 40<SP>1</SP> carried by chains 39 and 39<SP>1</SP> and the cores expanded by evaporating an internal liquid by means of hot air blowers 42. The coated fabric is then cooled by cold air from blowers 42, which also serves to contract the cores, and the fabric indexed forward to introduce a fresh length from the store into the coating station and to present the expanded fabric to a cutting station. The starting fabric may be of acrylic or polyacrylic fibres or fibres of chlorinated or fluorinated hydrocarbons such as PTFE. The coating or impregnating material may be thermoplastic material such as PVC, vinylidene polychloride, polychlorotrifluoroethylene, PTFE, or a rigid vinyl copolymer dissolved in a suitable solvent. Alternatively, polymerizable monomers such as epoxy, polyester or allalkyl resins can be used.